The present invention relates to an actuator for controlling the status of an electrical switch. More particularly, it pertains to an actuator designed to produce a change in (air pressure) which is transmitted to a remotely-located electrical switch that is sensitive to the change in air pressure, thereby altering the status of the switch.
To minimize the potential for electrical shocks, it is frequently desirable for an electrical switch to be located remote from the switch actuator, and for the actuator not to incorporate an electrical current for controlling the switch. This is especially true where the user is situated in a water environment, such as a bathtub or a whirlpool. In these environments, the user may want to control electrical lighting, a water heater, or a water pump. For convenience reasons, the switch actuators for these devices should be within reach of the user, and for the safety reasons, all electrical currents should be located distant from the user and the actuators.
Consequently, both switch actuators that produce a change in air pressure and electrical switches that respond to the change in air pressure have been developed. In U.S. Pat. No. 4,754,107, for example, master and slave units having variable volume chambers are in air communication with each other. Movement of a flexible bellows in the master chamber increases the air pressure in both the master and slave units. The increased pressure in the slave chamber activates an electrical switch.
In switch actuators of this type, the flexible bellows is not isolated from the person controlling the switch. Therefore, the user may press on the bellows from a variety of directions. The force applied to the bellows may be at an angle that is ineffective to operate the switch. Alternatively, the force may be in a direction that causes excessive wear of the bellows. Forces in undesirable directions may also result in accidental disassembly of the actuator. Furthermore, when the actuator is used in a public environment, an unprotected flexible bellows may be subject to vandalism.
It can therefore be seen that a need exists for an improved switch actuator incorporating a flexible bellows, where the actuator isolates and protects the bellows from the user and produces effective switch control on a repetitive basis.